MASSIVE THYMIC HYPERPLASIA SECONDARY TO GRAVES DISEASE

Objective: Graves disease (GD) has a well-known association with thymic hyperplasia, which is seen histo-logically in up to 38% of patients with GD. However, there have only been approximately 100 documented cases of Graves-associated massive thymic hyperplasia. Potential mechanisms of thymic pathology are reviewed. Methods: A 24-year-old female presented to the emergency department with dyspnea, palpitations, tachycardia, anxiety, and weight loss. She was evaluated for hyperthyroidism using labs (thyroid-stimulating hormone, free thyroxine, thyroid-stimulating immunoglobulins) and imaging (radioactive iodine uptake [RAIU] scan), leading to treatment with radioiodine. A computed tomography angiogram of the chest was also performed to evaluate for pulmonary embolism given the patient's presenting symptoms. Results: Our patient was found to have undetectable thyroid-stimulating hormone, elevated free thyroxine (2.9 ng/dL), and elevated thyroid-stimulating immunoglobulins (399%). Diagnosis of GD was confirmed on RAIU scan. The computed tomography chest angiogram demonstrated a significant anterior mediastinal mass (7.9 × 6.9 × 6.3 cm). Treatment with radioiodine led to reduction of the mass by 76% in volume. Conclusion: While the patient's thyroid labs and RAIU scan were consistent with GD, the presence of massive thymic hyperplasia was atypical. However, the resolution of thymic hyperplasia after radioiodine therapy, without the use of thymectomy, was similar to other reported cases.

Marine-Lenhart syndrome in two adolescents, including one with thyroid cancer: a case series and review of the literature

Background:The coexistence of functional thyroid nodules and Graves’ disease (GD) is a rare condition known as Marine-Lenhart syndrome. Thyroid cancer has been described in several adults, but never in children, with Marine-Lenhart syndrome. This paper discusses the challenges in diagnosis and the unique management of this condition in children, in the context of extant literature.Content:In this case report, two adolescent female patients with Marine-Lenhart syndrome, aged 15 and 16 years, exhibited biochemical evidence of hyperthyroidism, and were found to have unilateral hyperfunctioning thyroid nodules via thyroid scintigraphy. Additionally, both patients showed elevated thyroid-stimulating immunoglobulins (TSI) and increased glandular activity, confirming background GD. Notably, one patient was also diagnosed with intranodular thyroid cancer upon preoperative examination. Both patients were treated via surgical resection.Summary and outlook:Diagnosis of Marine-Lenhart syndrome can be made in patients with functional thyroid nodules and increased glandular activity on thyroid scintigraphy. Standard doses of radioiodine ablation are not effective in the majority of patients and should be avoided due to the increased risk for thyroid cancer, making thyroidectomy the preferred treatment.

Rhabdomyolysis Induced by Nonstrenuous Exercise in a Patient with Graves’ Disease

Hyperthyroidism can result in several musculoskeletal conditions such as thyrotoxic periodic paralysis, thyrotoxic myopathy, and thyroid ophthalmopathy. Rhabdomyolysis has been rarely reported to be associated with hyperthyroidism. We describe a 33-year-old man who presented with bilateral thigh pain and dark brown urine after regular squatting. He had a past medical history of hyperthyroidism but stopped taking it 2 months prior to admission. He was found to have rhabdomyolysis, myoglobinuria, and thyrotoxicosis. Presence of thyroid-stimulating immunoglobulins (TSI) and high radioiodine uptake confirmed a diagnosis of Graves' disease. He received aggressive fluid resuscitation and sodium bicarbonate intravenously along with monitoring fluid and electrolyte. Methimazole was also resumed. The patient responded to treatment and rhabdomyolysis gradually resolved. Therefore, nonstrenuous exercise can potentially induce rhabdomyolysis in patients with hyperthyroidism. Although hyperthyroidism is not widely recognized as a cause of rhabdomyolysis, it should be considered in the differential diagnosis of rhabdomyolysis.

Fetal Tachycardia Treated Successfully with Maternally Administered Propylthiouracil

Background. Fetal tachycardia may result from the transplacental passage of thyroid stimulating immunoglobulins in a patient with hypothyroidism secondary to ablation of Graves’ disease.Case. A 32-year-old woman, gravida 4, para 2, and abortus 1, with hypothyroidism and a history of Graves’ disease, presented at 23 6/7 weeks of gestation with a persistent fetal tachycardia. The treatment of the fetal tachycardia with maternally administered digoxin and Sotalol was unsuccessful. Maternal thyroid stimulating immunoglobulins were elevated, and treatment with maternally administered propylthiouracil (PTU) resulted in a normal sinus rhythm for the remainder of the pregnancy. An induction of labor was performed at 37 weeks. Four to five days after delivery, the neonate exhibited clinical signs of hyperthyroidism necessitating treatment.Conclusion. Fetal tachycardia resulting from the transplacental passage of thyroid stimulating immunoglobulins can be successfully treated with maternally administered PTU. The neonate needs to be followed up closely as clinical signs of hyperthyroidism may occur as thyroid stimulating immunoglobulins continue to circulate in the neonate, while the serum levels of PTU decline.